The incident began Tuesday afternoon, she said, when an off-duty officer at the Home Depot called to request backup officers for an arrest.

The chief asked for people to keep the officers, their families and the department in their prayers.

"We need you right now. Our hearts are very heavy," she said.

Dallas Mayor Mike Rawlings also tweeted on the shooting: "We are closely monitoring the situation in northeast Dallas and praying for our officers and their families."

No further details were immediately available.

Editor's Note: A previous version of the story stated one officer died; however, the originating station in Dallas has since retracted that statement and we have revised our story to no longer include the death.